Porsche 911 Turbo User Handbook Manual page 24

Electronically controlled all-wheel drive with Porsche Traction Management.
The synthesis of brains and brawn.
An engine's twisting power is clutch responded to relative
of limited use unless it can be front/rear speed differences to
turned into forward motion. This determine how much torque to
is no small challenge in the apply at either axle. The new
powerful 911 Turbo. To apply the generation of 911 Turbo, by
engine's 460 lb.-ft. of torque to contrast, employs an electronically
the road, Porsche engineers have controlled multi-disc clutch that
developed a new traction control responds to traction changes
system for the car's full-time all- almost instantaneously. Onboard
wheel drive. sensors measure a range of
values, including the rotational
In the previous 911 Turbo speed of all four wheels, the
(Type 996), a viscous multi-disc car's lateral and longitudinal
Electronically controlled multi-disc clutch
acceleration, and the current
steering angle. The sensor data
are analyzed in real time, enabling
immediate adjustments in the
torque split between the front
and rear axles.
Balanced performance.
The benefits are wide-ranging.
For example, if the rear wheels
lose traction under acceleration,
more drive torque is instantly
transmitted to the front axle. The
integral Anti-Slip Regulation (ASR)
function also minimizes wheel-
spin. When the vehicle is cornering,
Porsche Traction Management
(PTM) adjusts drive to the front
wheels in order to maintain
optimal lateral grip. On variable-
grip surfaces, traction is
enhanced using the Automatic
Brake Differential (ABD) function.
For optimal traction, manual-
transmission cars can also
be equipped with an optional
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mechanical limited-slip benefits of the new electronically
rear differential. controlled system are particularly
apparent in wet conditions or
Assisting Porsche Traction on snow.
Management is an upgraded
version of Porsche Stability
Management (PSM). Combined,
Active safety.
these systems ensure optimal
torque distribution as the road The system also plays a role in
changes beneath you—through emergency braking. When the
long straightaways, hairpin bends Anti-lock Brake System (ABS)
and the challenge of changing is activated, Porsche Traction
levels of road grip. The traction Management cuts all torque to
The 911 Turbo I Performance
All-wheel-drive system
the front axle, so that both front
wheels can be controlled
separately by the ABS without
being influenced by the rear-
wheel dynamics.
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